Sony Ericsson XZ Premium crashes after 7 months, then overheats / No warranty

After a short 7 months of use of my Sony Ericsson G8141 Experia XZ Premium, the phone crashed, without warning. Was sitting at a table, phone on the table, tried to open the screen - dead. It was working perfectly fine before that.The phone then proceeded to heat up at the rear of the phone. Went home and tried to put the phone on charger, although I know when I left the phone was on 93% and nothing. Took the phone into Vodacom and the phone went for "repairs". Then phoned Vodaworld and they tell me the phone is irrepairable due to a charger circuit track burnt, I must claim from my insurance, not warranty. In no way was the phone abused, dropped, no water or anything. Cannot believe it.